Field of the Invention
The present invention relates to wireless ad-hoc networks and more particularly to a system and method of providing soft time-division multiple access (Soft TDMA) for wireless ad-hoc networks.
Description of the Related Art
Attempts to address the performance degradation that occurs in wireless ad-hoc networks with contention-based Media Access Control (MAC) methods at higher traffic loads have typically taken two approaches. A first approach attempts to limit the incident traffic load from increasing to a level at or beyond which the degradation in performance becomes unacceptable. This approach is generally categorized as congestion control since the main emphasis is on preventing channel congestion by controlling the incident traffic load. However, since there is no change to the contention resolution behavior of the MAC, this approach does not improve the achievable network throughput.
A second approach attempts to modify the MAC behavior to more effectively use the available channel capacity based on the characteristics of the incident traffic. For example, if the application scenario requires each wireless node to regularly send traffic over the wireless medium and the data packets comprising the traffic are predominantly of one size or within a small range of sizes, a time-division multiple access (TDMA) scheme could be more efficient. With a TDMA-type scheme, a wireless node may perform regular transmissions without the need to contend for access for each transmission. However, replacing the contention-based MAC with a TDMA-based MAC can introduce other inadequacies, such as complexities and possible inefficiencies to support a mix of traffic with different characteristics and interoperability with existing wireless nodes if there is already a deployed population of wireless nodes with the contention-based MAC.
A solution is needed that can improve the achievable network throughput while being able to support a mix of different traffic types.